I know how to change default program to certain type of files, but I've been running to situations where I could use 2 defaults.

Lets take .html files for example. I have assigned Chrome to open all .html files on doubleclick, which is nice. As Im web developer, I usually need to open .html files also in textmate. For this to happen, I need to open context menu and select program from Open With menu.

Wouldn't it be great if one could Command+doubleclick to open that file with secondary program?

There's a bug where the shortcuts for Automator services don't always work until the services menu has been shown once from the menu bar. Another bug is that services that receive folders or files as input aren't available when folders are selected in column view in Finder.